1. Field of the Invention
The present invention relates to a system for cleaning equipment, and more particularly, to a system for cleaning equipment, such as molds, using a laser wherein degradation of the equipment during the cleaning operation is minimized or eliminated.
2. Description of the Prior Art
In a typical molding operation, a mold having interior surfaces configured to correspond to the shape of an article to be molded is mounted in a press and the material used to form the article is supplied to the mold and molded in the desired shape. When the article is removed from the mold, a certain amount of residual material may remain on the interior mold surfaces. For example, when a molded rubber article is formed, residual material in the form of small pieces of rubber and/or release agents remain within the mold and must be removed through a cleaning process.
Various cleaning processes have been used for cleaning molds and most known cleaning processes incorporate a media which is introduced into the interior of the mold to impart a physical force to any residual material on the interior mold surfaces whereby the material is physically removed from the mold. Early known cleaning processes incorporated glass beads as the cleaning media which would be blown or blasted into the mold to perform a sandblasting type of cleaning operation. Subsequently, plastic beads were introduced as the cleaning media in order to reduce the amount of abrasion and damage which may occur to the interior of the mold tooling. More recently, solid CO.sub.2 pellets have been used as the cleaning media in order to further reduce the abrasive affects of the cleaning operation on the tooling.
A problem associated with glass and plastic beads is the tendency of the bead media to become lodged or trapped within the mold which will have a deleterious effect on articles subsequently formed within the mold. Further, crevices in the mold can be difficult for the media to reach, particularly if the surfaces located within a crevice which cannot be directly blasted by the media. Also, the use of a cleaning media results in increased expense for operating the molding apparatus in that there is a continuing expense for the purchase and disposal of the media used for the cleaning.
In an alternative cleaning process, a laser is used to perform the mold cleaning operation. The laser has the advantage of avoiding the use of a physical cleaning media and thus simplifies the cleaning procedure. Such a laser cleaning device is disclosed in U.S. Pat. No. 5,373,140 issued to Nagy et al. and assigned to the assignee of the present invention.
One difficulty which has been identified in the cleaning of molds using a laser system has been the development of hot spots on the mold during the cleaning operation. When a hot spot develops on the mold surface, oxidation of the mold surface around the hot spot may occur. While such oxidation may not be readily visible when viewing the mold surface, the oxidation spots may result in discolored areas being formed on parts produced in the mold. Thus, the finished part may have areas which detract from its aesthetic appearance as a result of oxidation of the mold occurring during the cleaning operation.